反应详情

(S)-pipecolic acid (1.0 g, 7.7 mmol) was treated with trimethyl orthoacetate (15 ml, 171 mmol, 22 eq. 15 vol) and methanol (5 ml, 5 vol). The mixture was stirred and heated for 48 h and then concentrated in vacuo. The residue was dissolved in dichloromethane (10 ml) and filtered through a silica gel plug to yield N-acetylpipecolic acid, methyl ester (730 mg, 50%) which was racemic by GC analysis and had a 1H nmr spectrum which compared favourably with authentic material.

1. temperatureheated for 48 h
2. concentrationconcentrated in vacuo
3. dissolutionThe residue was dissolved in dichloromethane (10 ml)
4. filtrationfiltered through a silica gel plug